Speed Kit handles all resources of your website that are served through Speed Kit's Service Worker. But since Speed Kit cannot recognize dynamic content automatically, yet, we exclude the HTML file of your website by default as long as you check the box "My site is not static" in the installation wizard. That means that the auto-generated Speed Kit config you received for your website does not accelerate the HTML file.
Blacklisting the HTML file is necessary for auto-generated Speed Kit configurations because caching the HTML file is only safe for static websites. Whenever the website contains dynamic content (e.g. server-generated suggestions, a checkout cart, your personal history, whatever), caching the HTML file will make your users see outdated content – and this must not happen.
Speed Kit is able to accelerate your HTML file as well, but you have to configure it with the Dynamic Blocks feature to make sure that the personalized sections of your site are handled correctly. This really should be done by a developer, because it’s very technical and you need to understand what you are doing. If this is an option for you, please make sure to read the docs beforehand, specifically the following sections: